In the past few years, orbital angular momentum (OAM) has aroused great interest in the scientific communities, because it shows great potential for enhancing capacities of radio and optical communication systems. Here, we propose anisotropic metasurfaces to generate multiple OAM vortex beams at microwave frequencies. A phase compensation theory is presented, in order to determine the phase distributions on metasurfaces, This theory enables independent control of beam numbers, polarizations, orientations, and topological charges of OAM vortex beams, respectively. The metasurface is composed of anisotropic elements, whose reflection phases can be engineered separately in different polarization directions. The scheme is validated by both simulation and experimental results and shows great potential for the polarization division multiplexing in OAM communication systems.
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http://dx.doi.org/10.1364/OE.26.031664 | DOI Listing |
Phys Rev Lett
December 2024
Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA.
The topological magnetoelectric effect (TME) is a defining property of three-dimensional Z_{2} topological insulators that was predicted on theoretical grounds more than a decade ago, but has still not been directly measured. In this Letter we propose a strategy for direct measurement of the TME and discuss the precision of the effect in real devices with charge and spin disorder.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing, 100084, China.
Skyrmion bags, with arbitrary topological charge Q, have recently attracted much interest, since such high-Q topological systems could open a way for topological magnetism research and are promising for spintronic applications with high flexibility for information encoding. Investigation on room-temperature skyrmion bags in magnetic multilayered structures is essential for applications and remains unexplored so far. Here, we demonstrate room-temperature creation and manipulation of individual skyrmion bags in magnetic multilayered disks.
View Article and Find Full Text PDFSci Rep
January 2025
School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China.
Recently, vortex beams have been widely studied and applied because they carry orbital angular momentum (OAM). It is widely acknowledged in the scientific community that fractional OAM does not typically exhibit stable propagation; notably, the notion of achieving stable propagation with dual-fractional OAM within a single optical vortex has been deemed impracticable. Here, we address the scientific problem through the combined modulation of phase and polarization, resulting in the generation of a dual-fractional OAM vector vortex beam that can stably exist in free space.
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January 2025
Department of Technical Education, Uttar Pradesh, India.
In this work, Density Functional Theory (DFT) on Gaussian 09 W software was utilized to investigate the phenylephrine (PE) molecule (C9H13NO2). Firstly, the optimized structure of the PE molecule was obtained using B3LYP/6-311 + G (d, p) and CAM-B3LYP/6-311 + G (d, p) basis sets. The electron charge density is shown in Mulliken atomic charge as a bar chart and also as a color-filled map in Molecular Electrostatic Potential (MEP).
View Article and Find Full Text PDFNat Commun
January 2025
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, Dresden, Germany.
Charge-carrier compensation in topological semimetals amplifies the Nernst signal and simultaneously degrades the Seebeck coefficient. In this study, we report the simultaneous achievement of both a large Nernst signal and an unsaturating magneto-Seebeck coefficient in a topological nodal-line semimetal TaAs single crystal. The unique dual-high transverse and longitudinal thermopowers are attributed to multipocket synergy effects: the combination of a strong phonon-drag effect and the two overlapping highly dispersive conduction and valence bands with electron-hole compensation and high mobility, promising a large Nernst effect; the third Dirac band causes a large magneto-Seebeck effect.
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